Multi-stage friction pump



P 1, 1964 P. SCHLUMBOHM 3,146,939

MULTI-STAGE FRICTION PUMP Filed 001:. 25, 1962 INVENTOR.

United States Patent 3,146,939 MULTZi-STAGE FRICTION PUMP Peter Schlumbohrn, New York, N.Y.; Francis J. Gorman, executor of said Peter Schlumbohm, deceased Filed Oct. 25, 1962, Ser. No. 232,951 2 Claims. (Cl. 230-130) The present invention is a continuation-in-part of my copending application Ser. No. 780,562, now Patent No. 3,071,311, which itself is a continuation-in-part of Ser. No. 354,786, now Patent No. 2,877,865.

The application Ser. No. 780,562 claims a friction pump for centrifuging fluids, having a centrifuging space mounted for rotation around a shaft, comprising a plurality of superposed flexible discs mounted on said shaft and forming the walls of the centrifuging space between them and leaving a 360" open ejection slot at the periphery of the walls, one wall being of porous and flexible material and forming with its pores the intake passage for the fluid entering into the centrifuging space, and the other wall being of impervious material.

This renders an impeller with a one-side intake for the fluid to be pumped. In my Patent No. 2,910,223 I took advantage of this impeller to build a multistage compressor by arranging several impellers on a shaft and letting one impeller take-in the exhaust of the preceding impeller. I used a special casing to separate the various stages.

The present invention refers to a simplified casing.

The simplification is based on an inventive step, claimed in the parent application: to provide a frusto-conical casing in close proximity around the periphery of the impeller, the smaller end of the casing extending upstream of the impeller, guiding the fluid towards the porous disc, the larger end of the casing extending downstream of the pump, guiding the fluid which leaves the ejection slot.

The invention is illustrated, by way of example, in FIG. 1 and FIG. 2 of the accompanying drawings.

FIG. 1 is a side view, showing three impellers arranged on a common shaft with a common casing, the casing being shown in vertical cross section.

FIG. 2 is a cross section 22 of FIG. 1.

In FIG. 1 a shaft 1 is rotatable on supporting blocks 2, 3. Three arbors 9, 9', 9" are the bases of three impellers 4, 5, 6. Each impeller comprises one porous intake disc 7, 7, 7" and one impervious disc 8, 8', 8". The periphery of each impeller is surrounded by a frustoconical casing 11, 11', 11" as claimed in the parent application. The casing 11 of the first impeller is joined by a ice convergent wall 12, 12 to the wall of the casing of the next impeller.

The arrows illustrate the flow of fluid from a zone of starting pressure P0 into a pressure chamber with pressure P1 between impellers 4 and 5, from there into a pressure chamber P2 between impellers 5 and 6 and finally into a pressure chamber with pressure P3 downstream of impeller 6, where an exhaust tube 1.3 may be provided for delivery of the compressed gas.

The combined casings have a bellow-like shape. The structure may be reenforced by an outer tube 14, indicated in dotted lines.

Aside from the simplicity of structure, one great advantage of the new casing is, that the casing can be removed without dismantling, when the porous discs have to be replaced from time to time.

I claim as my invention:

1. A multistage centrifugal pump comprising a plurality of circular impellers fixed in spaced relation upon a common rotatable shaft, each impeller comprising a porous intake disc and an adjacent downstream impervious disc, to move fluid axially through said porous disc and radially outwardly between said discs, a casing surrounding said impellers and shaft and forming an intake at the upstream end thereof, an exhaust at the downstream end thereof and an intermediate bellows shaped portion defining adjacent the periphery of each impeller a frustoconical section of increasing diameter in the downstream direction and intermediate frusto-conical sections of decreasing diameter in the downstream direction connecting adjacent of said first mentioned sections to receive said radially outwardly moved fluid from one impeller and direct said fluid to the intake of the adjacent downstream impeller, thereby to provide an axial flow of fluid in increasing pressure stages.

2. Apparatus as set forth in claim 1 and in which said impeller discs are made of flexible material to allow removal of said casing without dismantling the same when said porous discs require replacement.

References Cited in the file of this patent UNITED STATES PATENTS 2,623,357 Birmann Dec. 30, 1952 2,632,598 Wales Mar. 24, 1953 3,071,311 Schlumbohm Jan. 1, 1963 FOREIGN PATENTS 439,542 France Apr. 6, 1912 114,335 Germany Oct. 18, 1900 

1. A MULTISTAGE CENTRIFUGAL PUMP COMPRISING A PLURALITY OF CIRCULAR IMPELLERS FIXED IN SPACED RELATION UPON A COMMON ROTATABLE SHAFT, EACH IMPELLER COMPRISING A POROUS INTAKE DISC AND AN ADJACENT DOWNSTREAM IMPERVIOUS DISC, TO MOVE FLUID AXIALLY THROUGH SAID POROUS DISC AND RADIALLY OUTWARDLY BETWEEN SAID DISCS, A CASING SURROUNDING SAID IMPELLERS AND SHAFT AND FORMING AN INTAKE AT THE UPSTREAM END THEREOF, AN EXHAUST AT THE DOWNSTREAM END THEREOF AND AN INTERMEDIATE BELLOWS SHAPED PORTION DEFINING ADJACENT THE PERIPHERY OF EACH IMPELLER A FRUSTOCONICAL SECTION OF INCREASING DIAMETER IN THE DOWNSTREAM DIRECTION AND INTERMEDIATE FRUSTO-CONICAL SECTIONS OF DECREASING DIAMETER IN THE DOWNSTREAM DIRECTION CONNECTING ADJACENT OF SAID FIRST MENTIONED SECTIONS TO RECEIVE SAID RADIALLY OUTWARDLY MOVED FLUID FROM ONE IMPELLER AND DIRECT SAID FLUID TO THE INTAKE OF THE ADJACENT DOWNSTREAM IMPELLER, THEREBY TO PROVIDE AN AXIAL FLOW OF FLUID IN INCREASING PRESSURE STAGES. 